9 things to know about New Jersey’s impending return to winter

The next 24 hours are going to be quite active, with a wide range of weather conditions. Bottom line: we are about to experience a harsh transition from our brief springlike January thaw back to much colder winterlike weather.

1.) Warmth

Last Sunday morning, the weather station at Atlantic City International Airport hit a record low temperature of -3 degrees. On Thursday afternoon, ACY set a new record high temperature of 62 degrees. This week's warmup has been welcome, after two consecutive weeks stuck below freezing. The warmth looks to peak Friday, before crashing to the ground early Saturday.

HRRR model temperature forecast as of Friday afternoon, showing near-record high temps in the lower 60s across New Jersey. (College of DuPage Meteorology)

Even with the cloudy skies, wind, fog, and rain in the forecast for Friday (keep reading), I expect thermometers to reach the 60 degree mark for most of New Jersey. That's about 20 degrees above normal for mid-January, and close to record highs. (Although I believe records for Friday will remain intact: EWR 67, TTN 68, ACY 65.)

Rule of thumb: Temperatures will generally hold steady in the 50s and 60s Friday and Friday night.

2.) Rain

Luckily, it is because of those aforementioned balmy temperatures that our incoming pair of storm systems will produce almost exclusively rain. (Again, keep reading for a limited threat of wintry weather.)

NAM model rain forecast as of Friday afternoon. It's going to be a very wet day. (College of DuPage Meteorology)

As of this writing, showers have already begun pushing into the Garden State. Pockets of steady (possibly heavy) rain will develop throughout Friday. (The heaviest rain unfortunately looks to coincide with the Friday evening commute.) With marginal instability in the atmosphere, a few rumbles of thunder will be possible too. While I still don't think it's going to be a washout of a day (meaning solid rain, all day), it's definitely going to be wet. Umbrellas up!

We should get a break in the rainfall action Friday evening, before system number two takes over early Saturday morning. Expect one more brief round of moderate to heavy rain around daybreak Saturday.

Final rainfall totals will be highly dependent on whether a given location sees any big downpours or not. I think everyone in New Jersey will experience at least a half-inch of rainfall — good news since about 39% of the state remains "abnormally dry" as of this week. On the high side, models suggest upwards of 2 inches of rain will be possible from Friday morning through Saturday morning.

3.) Melt

The combination of warmth and heavy rain is perfect for rapid melting of the snow/ice leftover from last week's blizzard. As I pointed out in Thursday morning's weather blog entry, this will likely lead to several issues:
--At the very least, the ground will become a slushy mess from the massive snowmelt and heavy rain.
--Storm drains blocked by snow and/or leaves may prevent runoff from exiting the street, leading to ponding and flash flood issues.
--There's lots of ice in our oceans, bays, canals, rivers, streams, and creeks. As that ice melts and breaks apart, it will flow downstream and potentially "jam" against bridges, banks, or other icebergs. That can cause water to backup and rise further upstream, again leading to a flooding risk.

4.) Fog

HRRR model visibility forecast for Friday. The black contour shows the potential for thick fog across all of New Jersey as our warm, most air clashes with the cold snow on the ground. (College of DuPage Meteorology)

Rising humidity, along with the temperature contrast between (cold) snow and (warm) air/rain will likely lead to pockets of dense fog. So, even when it's not raining on Friday, visibility may be significantly impaired. Remember to use low-beam headlights and slow down when driving through foggy areas.

5.) Wind

This stormy setup will also drive some stronger wind gusts through the Garden State.

There had been a Wind Advisory posted for part of New Jersey, but that was cancelled as potentially damaging winds never developed. (A good decision in my opinion — my best estimate for ambient wind gusts has been around 30 mph.) A few stronger gusts are possible from embedded thunderstorms.

6.) Cooldown

NAM model temperature forecast as of early Saturday morning, showing colder air pushing into the Garden State. (College of DuPage Meteorology)

As the rain wraps up Saturday morning, a strong arctic cold front will officially put an end to the warmer temperatures. Colder air will begin arriving in NW NJ around 5 a.m. Saturday and SE NJ by around 9 a.m. Thermometers will plunge very quickly from the 50s to below freezing, probably by midday.

Such a sharp temperature drop may lead to a flash freeze — puddles from the extended period of rain may not have time to evaporate before temps tumble below freezing. Therefore, we'll have to be on the lookout for some serious and sudden icing problems.

7.) Wintry Mix

GFS precipitation type forecast as of 7 a.m. Saturday, illustrating the potential for wintry mix (pink/purple) in North Jersey. (College of DuPage Meteorology)

The timing of the end-of-rain and the beginning-of-cooldown on Saturday morning is dicey.

As temperatures start to fall (at the surface and/or up in the atmosphere), a brief change to wintry mix precipitation is possible. It would be mainly sleet and freezing rain. This would be mainly a problem for North Jersey (above Interstate 78, especially in the higher elevations). Ice accumulations would be limited. And the time window for such wintry weather is also narrow, between about sunrise and mid-morning Saturday.

Current advisories from the National Weather Service. Purple=Winter Weather Advisory.

However, it doesn't take much ice at all to create significant travel headaches. A Winter Weather Advisory has been issued for Sussex and Warren counties from 4 a.m. to 10 a.m. Saturday. (That advisory may be expanded based on realtime precipitation type observations on Saturday.)

8.) Deep Freeze

And just like that, the arctic chill is here for the foreseeable future. Again.

While temperatures may occasionally pop above the freezing mark next week, I don't see another substantial warmup in New Jersey's immediate future. In fact, it looks like thermometers will be stuck below normal for at least the next 9 or 10 days. Highs generally around 30, lows mostly in the frigid teens.

Yes, it's January and it's supposed to be cold. But yet again, this arctic blast presents an extended stretch of unseasonable cold that will be bitter, uncomfortable, and potentially dangerous.

9.) Snow

We're still monitoring the potential for some wintry weather for next Tuesday-Wednesday. This appears to be a pretty classic two-prong setup, with a clipper system from the west "phasing" with a newly forming coastal low. The combination could lead to a lot of snow, but the timing and location of the two systems have to be just right.

Models have been wishy-washy about snow totals thus far, with the Euro most bullish (upwards of 10 inches) and the GFS much meeker (holding steady around 3 inches). With our newly refreshed arctic air mass, the potential for accumulating snow is certainly there. But it would be incredibly foolish to post definitive snow totals or expectations at this time — let's just keep it at "worth watching" status for the next day or two.

Dan Zarrow is Chief Meteorologist for Townsquare Media New Jersey. Follow him on Facebook or Twitter for the latest forecast and realtime weather updates.